Fuel injection pump device and method for settling the same

ABSTRACT

A fuel injection pump device comprising a plunger (8) facing a pressurizing chamber (20) and actuated by a cam (12), a control sleeve (14) mounted on the plunger (8) in a fuel chamber (15) , an inclined groove (8d) and longitudinal groove (8c) provided on one of the plunger (8) or the control sleeve (14) for controlling the communication of the pressurizing chamber (20) and the fuel chamber (15) by way of an oil passage (8a) formed in the plunger (8), and control ports (14a) provided on the other of the plunger (8) or the control sleeve (14), which cooperates with both of the grooves (8c) and (8d). The effective stroke of the plunger (8) can be controlled by turning the plunger (8) around its axis to change the relative position of the inclined groove (8d) and longitudinal groove (8c) and the control ports ( 14a), and the prestroke thereof, this is a fuel injection timing, can be easily controlled only by moving the control sleeve (14) in the direction of the plunger axis. Thus, a centrifugal auto-timer becomes useless.

TECHNICAL FIELD

The present invention relates to a fuel injection pump device forinjecting fuel into the combustion chamber of an internal combustionengine.

BACKGROUND ART

A fuel injection pump device for pumping fuel into the fuel injectionnozzle of a Diesel engine has been hitherto composed so that the controlof a fuel injection quantity is carried out by turning a plunger forpressurizing the fuel in the pump, and composed so that the control of afuel injection beginning time is carried out by changing the rotatingphase of a cam shaft for driving said plunger, which is driven by theengine, with respect to the crank angular phase of the engine by use ofa centrifugal auto-timer provided on the cam shaft. In the case wherethe injection timing is controlled, however, the inertia mass of the camshaft is relatively larger and the pump driving torque transmitted fromthe cam shaft to the plunger is large, and such a conventional fuelinjection pump device is therefore disadvantageous: a large-sized timermust be used as an inevitable consequence, the cost is accordinglyincreased and the whole of the pump is made large-scaled.

The conventional pump device shown in FIG. 1 has the following defects.The reference numeral 01 represents a housing, in which a barrel 02 isarranged in its upper part and a cam shaft 04 is arranged in a cam shaftcase 03 in its lower part, and the head 06 of a plunger 05 is insertedand slidably arranged in said barrel 02.

A spring shoe 07 is mounted on the center of said plunger 05 and pressesdown the plunger 05 by virtue of a spring 08 placed between the plunger05 and the pump housing 01.

Said plunger 05 has an oil port 010 provided therein so as tocommunicate the head 06 and its lower body portion 09 with each other,and a control sleeve 011 which is turnable and slidable up and down ismounted on the lower body portion 09 and arranged so as to open or shutsaid oil port 010.

Said control sleeve 011 has an upper lead 012 and an lower lead 013formed thereon. The sleeve is turned by the movement of an injectionquantity control rod 020 in the normal direction to FIG. 1, thereby tocontrol the fuel injection quantity, and the sleeve is slided verticallyby way of an eccentric pin 015 by an injection timing control rod 014,thereby to control the fuel injection timing.

In the aforementioned composition in which fuel fed from a fuel source(not shown) such as a feed pump is supplied to a fuel chamber 016 formedin the housing 01 and remains there, however, there is a need ofproviding a spill-way for the fuel in order to actuate a tappet 017provided beneath the plunger 05, and a spill port 018 is thereforeformed in the said tappet 017, through which spill port 018 a part ofthe fuel is supplied to the cam shaft case 03.

Said housing 01 is accordingly filled with the fuel and the lubricationof said tappet 017, cam shaft 04 and the likes will be carried out bythe fuel itself. Perhaps, seizure is frequently caused to happen becausethe surface pressure in each lubricating part is too high.

Since the conventional pump device mentioned above is composed so thatall of the cam shaft 04, the tappet 017 driven by the cam shaft, theplunger 05 and the spring shoe 07 are sliding in the fuel and theresistance of the fuel becomes therefore larger, it has disadvantagessuch as a difficult revolution of the engine at a high speed and anexcess of heat generated by this resistance.

DISCLOSURE OF INVENTION

It is the main object of this invention to obtain an injection pumphaving a simple structure with an auto-timer omitted, in which thecontrol of a fuel injection timing can be realized by a small operatingforce.

In order to achieve this object, the present invention proposes a fuelinjection pump device characterized in that a control sleeve is slidablymounted on the outer periphery of a plunger and said control sleeve ismoved in the axial direction of the plunger thereby to control theinjection timing of fuel.

According to this composition, it is sufficient only to move the controlsleeve in said axial direction, with a small force required for thisoperation, and it is possible to make up the structure of an injectiontiming control member for actuating the control sleeve simply.

Since the delivery pressure from the fuel injection pump device isfurthermore prevented from rising more by moving the control sleeve toadvance the injection timing when the engine is in a high speed region,the fuel injection pump is not damaged. In addition, since the fuelinjection pump is not damaged even when the engine is in the high speedregion, its delivery pressure in the medium and low speed regions of theengine can be increased, the fuel consumption can be lowered and theblack smoke in the exhaust gas can be reduced in quantity.

It is another object of the present invention to obtain an injectiontiming settling method in which the injection timings of a fuelinjection pump device for a plurality of cylinders in an engine can befinely regulated quickly, easily and positively so as to be matched oneanother.

The first invention for achieving this object comprises attachingmovably an injection timing control member for moving a control sleeveon a control shaft, then moving the control sleeve to position thecontrol sleeve to a plunger, and fixing the injection timing controlmember to the control shaft.

The second invention comprises removing a delivery valve from a fuelinjection pump device and connecting a pressurized fluid source theretoin place of the delivery valve, moving a control sleeve, and fixing aninjection timing control member to a control shaft at the position wherethe pressure of fluid has been changed.

By the abovementioned composition, it is possible to carry out easilythe adjustment of the initial position of the injection timing controlmember to the control sleeve.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a conventional fuel injection pump,

FIG. 2 is a side view showing the first embodiment according to thisinvention,

FIG. 3 is a side view of FIG. 2 seen from the arrow III,

FIG. 4 is a sectional view of FIG. 2 taken along the line IV--IV andseen from the arrows,

FIG. 5 is an exploded perspective view showing important parts,

FIG. 6 is an enlarged perspective view of the main parts of a plunger 8and a control sleeve 14,

FIGS. 7 to 10 each are an operation illustrative view showing theoperation of the plunger 8 and control sleeve 14 in their relativerelated position,

FIGS. 11(a)-11(e) are operation illustrative views showing the pumpingoperation caused by the plunger,

FIG. 12 is a sectional view of FIG. 2 taken along the line XII--XII andseen from the arrows,

FIG. 13 is a sectional view of FIG. 12 taken along the line XIII--XIIIand seen from the arrows,

FIG. 14 is a view of the actuating circuit for an electromagneticsolenoid 44,

FIGS. 15 to 17 each are a front view showing a modification of a controlgroove cut on the outer peripheral surface of the plunger,

FIG. 18 is a table representing the dimensions of the main parts of thefuel injection pumps used for the respective engine mechanisms,

FIG. 19 is a graph showing the relation between the average oil feedratio and (plunger diameter D)² ×cam lift h,

FIG. 20 is a graph showing the relation between the piston displacementper each cylinder of the engine and the geometrical average oil feedratio,

FIG. 21 is a graph showing the relation between the revolution number ofa cam shaft and the internal pressure on the pump side,

FIG. 22 is a view of a cam profile,

FIG. 23 is a cam diagram,

FIG. 24 is a table showing the dimensions of the parts of the fuelinjection pumps having performances designated by the points P, Q, R, S,T and U in FIG. 20,

FIG. 25 is a characteristic diagram obtained in the first embodiment,

FIG. 26 is a sectional view showing the second embodiment according tothe invention,

FIG. 27 is a perspective view of the main parts of the injection pumpshown in FIG. 26,

FIGS. 28(a)-28(c) are operation illustrative views of a plunger and acontrol sleeve,

FIG. 29 is a transverse sectional view of the main parts of FIG. 28(a),

FIG. 30 is a transverse sectional view of the main parts of FIG. 28(c),

FIG. 31 is a perspective view of the main parts of an operation shaftused in another modification of the second embodiment,

FIG. 32 is a chart of a control circuit in the third embodimentaccording to the invention,

FIG. 33 is a side view of the injection pump shown in FIG. 32,

FIG. 34 is a diagrammatic view showing the distribution device of anfuel injection pump in the fourth embodiment according to thisinvention,

FIG. 35 is a front view of the cam of a fuel injection pump in the fifthembodiment according to the invention,

FIG. 36(A) is a perspective view of a delivery valve,

FIG. 36(B) is a front view thereof,

FIG. 37 is a characteristic diagram of a cam,

FIG. 38 is a sectional view of an injection pump of the sixth embodimentaccording to the invention,

FIG. 39 is a sectional view of the main parts taken along the lineXXXIX--XXXIX of FIG. 38,

FIG. 40 is a side view of FIG. 39,

FIG. 41 is an upper end view of a barrel 4 in the seventh embodimentaccording to the invention,

FIG. 42 is a sectional view of a pump in the eighth embodiment,

FIG. 43 is a sectional view of FIG. 43 taken along the lineXXXXIII--XXXXIII and seen from the arrows,

FIG. 44 is a side view of FIG. 43,

FIG. 45 is an exploded perspective view of the injection quantityregulation member of the injection pump shown in FIG. 42,

FIG. 46 is a sectional view of a pump in the ninth embodiment,

FIG. 47 is a sectional view of FIG. 46 taken along the lineXXXXVII--XXXXVII and seen from the arrows,

FIG. 48 is a side view of FIG. 47,

FIGS. 49(A) to 48(E) illustrate a developmental view showing the fuelinjection mode of the pump shown in FIG. 46,

FIG. 50 is a sectional view of a pump in the tenth embodiment,

FIG. 51 is a perspective view showing the control sleeve and controlshaft taken from FIG. 50,

FIG. 52 is a perspective view showing a modification of the tenthembodiment similarly to FIG. 51,

FIG. 53 is a longitudinal sectional view of the main parts of a pump inthe eleventh embodiment,

FIG. 54 is a sectional view of FIG. 53 taken along the lineXXXXXIV--XXXXXIV and seen from the arrows,

FIG. 55 is a longitudinal sectional view of another modification of theeleventh embodiment similarly to FIG. 53,

FIG. 56 is a sectional view of FIG. 55 taken along the lineXXXXXVI--XXXXXVI and seen from the arrows,

FIG. 57 is a pump characteristic diagram,

FIG. 58 is a sectional view of the main parts of a pump in the twelfthembodiment, and

FIG. 59 is a sectional view of a pump in the thirteenth embodimentaccording to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

A number of embodiments according to the present invention will bedescribed in detail with reference to the accompanying drawings.

In the first embodiment shown in FIG. 2 to FIG. 25, the referencenumeral 2 represents a housing of an in-line fuel injection pump for aDiesel engine, and 4 represents one of a plurality of barrels held inthe housing, which barrels 4 are positioned so that their axes stand inrows on one plane in the housing 2. This barrel 4 is composed of a firstbarrel part 4a and a second barrel part 4b press-fitted thereon. Thereference numeral 6 represents a delivery valve holder fixed on the topof each barrel 4, which holder is to be connected to the respectivecylinders of an engine; 7a is a delivery valve; 8 is a plunger slidablymounted in each barrel 4; 10 is a spring for biasing the plungerdownwards; 12 is a cam interlocked with a driving shaft (now shown) ofan engine to push up the plunger 8; 14 is a control sleeve slidablymounted on the outer periphery of the plunger 8; 16 is a guide pin fixedon each barrel 4 and engaged in a guide groove 17 of the control sleeve14 to restrain its turn; and 18 is a sleeve turnably supported on thebarrel 4 but non-turnably engaged with the plunger 8. The plunger 8 hasan oil passage 8a which communicates its upper end face and itspheripheral side to each other, peripheral side openings 8b formed onthe peripheral side in communication with the oil passage 8a, alongitudinal groove 8c cut on the peripheral side so as to continue tothe opening 8b and to run along the axis of the plunger 8, and aninclined groove 8d intersecting this longitudinal groove 8c and slantingto the plunger axis, wherein a control groove is formed by both thesegrooves 8c and 8d and the oil feed ports 8b (which will be hereinaftercalled "the openings"). In the control sleeve 14, on the other hand,control ports 14a are perforated to define a fuel injection end. Thecondition which is required to inject fuel when the plunger 8 makes agiven effective stroke as shown in FIG. 7 will be stated below.Representing the vertical width or length of the control sleeve 14 bythe sign l₀ and the length including the longitudinal groove 8c and theopening 8b by the sign l₁, namely, it is required that the relation l₀>l₁ is satisfied. Representing the length between the upper edge of thecontrol port 14a and the upper end of the control sleeve 14 by the signl₄ and the length between said upper edge of the control port 14a andthe upper end of the longitudinal groove 8c by the sign l₃, it is alsorequired, as a condition for preventing the two-stage blasting of fuelat the injection end when the plunger 8 injects the fuel at the minimumeffective stroke as shown in FIG. 8, that the relation l₃ ≧l₄ issatisfied. And, it is required as a condition that the plunger 8 ispermitted to move up and down at the position where the control port 14aconfronts the longitudinal groove 8c as shown in FIG. 9, this is acondition for determining no injection of fuel, that the relation l_(l)>l₂ is satisfied, representing the length between the lower edge of thecontrol port 14a and the lower end of the control sleeve 14 by the signl₂. It is further required that the relation l₁ ≧l₄ is satisfied, as acondition that no injection of fuel can be positively realized even whenthe control port 14a is blocked up at the lower edge of the opening 8bby the plunger 8, under the state of said no injection operation asshown in FIG. 10. In FIG. 4, the reference numeral 15 represents a fuelchamber for storing fuel fed from a feed pump (not shown), wherein thefuel is not leaked into a cam shaft case 13, because the plunger 8 isinserted in the cylindrical second barrel part 4b, with an oil-tightstate held between them. The reference numeral 21 represents an oil feedopening through which lubricating oil is fed to the cam shaft case 13,and 23 represents a guide pin protruded on a tappet 25 and slidablyengaged in a guide groove 27 cut on a housing 2. Although notillustrated in FIG. 5, the reference numeral 29 shown in FIG. 4represents an adjustment screw (not shown in FIG. 5 and FIG. 12) screwedin a screw hole of an operation shaft 26 mentioned below, wherein thefuel injection timing can be finely adjusted by relaxing the screw 29 torotate a lever 28 properly.

When the cam 12 is rotated one time by a cam shaft 12a driven by therotating force receiving from the driving shaft of the engine and theroller 25a of the tapper 25 is pressed by the cam 12, according to theabovementioned composition, the plunger 8 will be reciprocated upwardsby a given lift or vertically at one stroke.

Now, the course from the state shown in FIG. 4 to the state in that theplunger 8 is pressed by the cam 12 to pump out the fuel will bedescribed here with reference to FIG. 11(a) to (e) [wherein the controlsleeve 14 shall be in a fixed position between the states (a) and (b)].When the related position of the plunger 8 and the control sleeve 14 isin the state shown in FIG. 11(a) or the opening 8b is not still blockedup completely by the control sleeve 14, the fuel is not pumped outbecause a pressurizing chamber 20 and the fuel chamber 15 are incommunication with each other. After the opening 8b is then blocked upby the control sleeve 14 as shown in FIG. 11(c) via the state of FIG.11(b), the pressurizing chamber 20 is interrupted from the fuel chamber15 and pressurized by the plunger 8. This stroke of the plunger 8 whichmoves between the states (a) and (c) is called a prestroke. When theplunger 8 continues to rise as shown in FIG. 11(d) from the state ofFIG. 11(c), the delivery pressure in the pressurizing chamber 20overcomes the spring force of a spring 7b in the delivery valve holder 6and the delivery valve 7a is opened so that high-pressure fuel is fed toan injection nozzle V through an injection tube 6a. Thus, the fuel isbeing pumped out until the inclined groove 8d of the plunger 8communicates to the control port 14a as shown in FIG. 11(e). When theinclined groove 8d gets to face the control port 14a as shown in FIG.11(e), the pressurizing chamber 20 begins to communicates with the fuelchamber 15 by way of the oil passage 8a, opening 8b and longitudinalgroove 8c, and as a result, the pumping of fuel comes to an end. Sincethe inclined groove 8d extends on the outer periphery of the plunger 8so as to slant with respect to its axis, as can be seen from FIG. 6, theconfrontation time of the inclined groove 8b with the control ports 14aof the control sleeve 14 in the stroke of the plunger 8 can be changedby the turning displacement of the plunger 8 caused by the sleeve 18,whereby the fuel injection quantity in one stroke of the plunger 8 canbe regulated. In addition, the displacement of the sleeve 18 in itsturning direction is carried out by displacing a rack 24 which engageswith a ball 22 secured on the sleeve 18 in its longitudinal direction.

The fuel injection timing control mechanism will be described here. Thecontrol of the fuel injection timing is conducted by the slidingdisplacement of the control sleeve 14 along the plunger 8, and thissliding displacement is carried out by means of an operation shaft 26supported in the housing 2 so as to lie by the side of the controlsleeve 14 and having its axis on one straight line parallel to a planeon which the aforementioned barrels 4 stand in rows and perpendicular tothe axis of the plunger 8, a lever 28 fixed on the operation shaft 26and extended from the operation shaft toward the plunger 8, and anotched groove 14b formed on the outer peripheral surface of the controlsleeve 14, which is engaged with the fore end of the lever 28 tointerlocked the turning displacement of the level 28 around theoperation shaft 26 and the sliding displacement of the control sleeve14. The outer peripheral surface of the lever 28 at its end has such acurvature that it is always in contact with the inner peripheral surfaceof the notched groove 14b, without giving any play between them. As wellshown in FIG. 12, the support part 26a of the operation shaft 26 at eachend is supported on the housing 2 by way of a bearing 30 having an outerdiameter which is larger than an external dimension including theoperation shaft 26 and lever 28 in the direction of the diameter of theoperation shaft 26, with a plate 32 disposed between one end of thebearing 30 and the housing 2. In addition, the reference numeral 34represents a snap ring which serves to prevent the bearing 30 secured inthe housing 2 from slipping out of the housing, and 36 represents apositioning pin embedded in the bearing 30 and running through a plate32 to engage with the housing 2. The fixing of the operation shaft 26 isconducted by mounting each barrel 4, plunger 8 and control sleeve 14within the housing 2, and then inserting the operation shaft 26 into thehousing 2 from its end.

The turning displacement of the operation shaft 26 is conducted by meansof an operation lever 40 fixed on one end of the operation shaft 26 andan electromagnetic solenoid 44 supported on the housing 2 by a bracket41, which turns the operation lever 40 by way of a slider 42, as shownin FIGS. 2, 3 and 5. In order to operate the electromagnetic solenoid 44with accuracy, a potentiometer 46 for measuring the turning displacementof the operation lever 40 is further supported on the bracket 41. Asshown in FIG. 14, a control unit 52 is composed so that variousinformations on the operating state of the engine from operating stateinformation sources 50, for example an engine speed, degree of anaccelerator pedal trod, temperature of cooling water, temperature ofintake air, boost pressure of an air intake system and temperature ofexhaust gas, and the information on the turning displacement of theoperation shaft 26 from the potentiometer 26 are sent to the controlunit and these informations are calculated synthetically, thereby toobtain a control of accurate injection timing. It is possible to adopt adifferential transformer type sensor in place of this potentiometer 26.In the aforementioned embodiment, it is also possible to turn theoperation lever 40 by a hydraulic cylinder in place of theelectromagnetic solenoid 44.

Furthermore, the rack 24 constitutes a fuel injection quantity controlmember, and the operation shaft 26, operation level 40 and slider 42constitute a fuel injection timing control member. A fuel injectioncontrol means is made up of a governor (the minimum-maximum type or theall-speed type) (not shown) for driving the rack 24, the control unit 52and the electromagnetic solenoid 44.

Since the first embodiment has the aforementioned composition, it hassuch operational effects as mentioned below. By turning the plunger 8around its axis to change the relatively related position of the controlport 14a to the inclined groove 8d forming a part of the control groove,namely, the effective stroke of the plunger is changed whereby the fuelinjection quantity can be regulated. By causing the longitudinal groove8c to accord with the control port 14a, the state of no fuel injectioncan be achieved as shown in FIG. 9. And further, the turningdisplacement of the operation shaft 26 having the lever 28 causes thecontrol sleeve 14 to displace in the direction of the plunger axis.Thus, the prestroke of the plunger is changed, whereby the injectiontiming can be adjusted. Since the sizes of the respective parts betweenthe plunger and control sleeve are set so that the relations l₀ >l₁ [theexpression (1)], l₁ >l₂ [the expression (2)], l₁ ≧l₄ [the expression(3)] and l₃ ≧l₄ [the expression (4)] may be satisfied, as have beenillustrated in FIGS. 7 to 10, the following conditions will be definedrespectively: (a) the condition of enabling the injection of fuel inaccordance with the expression (1); (b) the condition of ensuring noinjection of fuel in accordance with the expression (2); (c) thecondition of obstructing positively the fuel injection under theoperating state of no injection in accordance with the expression (3);and (d) the condition of obstructing positively the two-stage blastingof fuel by causing the upper end of the longitudinal groove 8c to faceinto the fuel chamber 15 from the upper end of the control sleeve 14,even if the control port 14a is not in communication with the controlgroove when the plunger 8 is displaced up to the top dead center asshown in FIG. 9, in the case that the fuel is being injected at theminimum effective stroke of the plunger, in accordance with theexpression (4). Therefore, accurate controls of the fuel injectionquantity and injection timing can be realized, and the injection timingcontrol can be effected in an electronic control mode because theinjection timing is controllable by a small operating force. Because ofno requirement of such a timer as used in a conventional device, it ispossible to simplify the structure of this fuel injection pump devicecorrespondingly. Furthermore, since the first embodiment has such astructure that the plunger 8 is oil-tightly inserted in the lowercylindrical portion of the second barrel part 4b, it is possible toavoid the flowing of the fuel in the fuel chamber 15 into the cam shaftcase 13. In the use of a pump having such a structure that its dischargepressure or pump pressure is increased by modifying the profile of thecam 12 to make the cam lift larger, while keeping the diameter of theplunger shown in FIG. 4, or enlarging only the plunger diameter, withthe cam lift kept as it is, it is easily enabled to use the pump under apressure lower than its withstanding pressure, if an advancing operation(by the downward movement of the control sleeve 14) is carried outthrough the aforementioned injection timing control, when the pumppressure reaches near to the withstanding pressure of the pump, this iswhen the engine is in a high speed region. And, it is thereby possibleto make larger the discharge pressure of the pump in the medium and lowload regions of the engine, with obtaining various operational effects,for example of seeking the increase in the output power of the engine inthe same regions.

Although the injection quantity control has been conducted by turningthe plunger 8, in the aforementioned first embodiment, it may becomposed so that the control sleeve is not only moved up and down by oneoperating link system, but also turned around the plunger axis. Thecontrol groove has been provided in the plunger 8 and the control ports14a in the control sleeve 14, but the control groove may be provided onthe side of the control sleeve and the control ports on the side of theplunger, respectively. In addition, the control groove has been cut onlyon the peripheral surface of the plunger 8 at one side, but it may befurther provided on the peripheral surface thereof at the other side. Inthe first embodiment, two openings 8b running through the plunger andtwo control ports 14a of the control sleeve have been provided, but oneopening and one control port may be provided at the positions where theyconfront with each other. As shown in FIG. 15, a modification of thecontrol groove in the aforementioned embodiment may be a control groovecomprising openings 8b communicating with a longitudinal groove 8c, aninclined groove 8d and the oil passage 8a in the plunger. In this case,the inner diameter d₁ of the control port is set to be at least equal toor larger than the distance d₀ between both the grooves 8c and 8d, inorder to ensure a state of no fuel injection. The control groove may befurther formed as shown in FIG. 16 and FIG. 17. In the aforementionedfirst embodiment, furthermore, there may be provided a notch along boththe inner and outer peripheral surfaces of the upper end of the controlsleeve 14 or a notch on the lower end of the first barrel part 4a,wherein even when the control sleeve gets into contact with the lowerend of the first barrel part 4a, with an oil-tight state formed betweenthem, fuel will be discharged into the fuel chamber through said notch,with an operational effect of preventing the two-stage blasting of fuel.

Referring to an injection pump having such a composition that thediameter of the plunger 8 is 12 mm and the lift of the cam 12 (which hasa cam profile shown in FIG. 22) is 14 mm, as shown at the point P inFIG. 20, and the cam diagram shown in FIG. 23 is obtained, by way ofexample, the operational effect thereof will be described.

As shown in FIG. 21, the relation between the revolution number of thecam shaft and the delivery pressure of the pump is represented by thegraph M. Assuming that the limit of the withstanding pressure in use ofthe pump is 800 kg/cm² at that time, the delivery pressure for fuel isincreased by the plunger 8 with the increase in the engine speed, whenthe cam angle shown in the cam diagram of FIG. 23 falls within the rangeθ₁ in the so-called medium and low engine speed regions wherein therevolution number of the cam shaft varies from 500 to about 900 r.p.m.When the revolution number of the cam shaft becomes about 900 r.p.m.,the delivery pressure reaches the withstanding pressure in use of thepump. At about 900 r.p.m., or when the revolution number of the camshaft reaches the point M'", the control sleeve 14 is moved downward bya given distance along the plunger 8. Thus, the prestroke of the plunger8 becomes short and as a result, fuel is injected with the speedconstant directed in the direction of the arrow, or the cam anglefalling within the range θ₂, as shown in FIG. 23. In the high speedregion of the engine, therefore, fuel is supplied from the fuelinjection pump to the engine at the constant and maximum deliverypressure M" regardless of the engine speed, as shown in FIG. 21. And atthe same time, the injection timing is controlled so as to be advanced,whereby the fuel is injected into a combustion chamber at a proper timeand mixed with air in said chamber for combustion.

The dimensions of the main parts of fuel injection pumps which have beenalready known in the market and used in various types of Diesel engines(injection pumps having such a structure that the injection timing isadjusted by a centrifugal auto-timer), are tabulated as shown in FIG.18. Plotting the average oil feed ratios (mm³ /deg) on the abscissa andthe values of (plunger diameter)² ×cam lift on the ordinate as to thetypes A to J from the table of FIG. 18, there is obtained the graphshown in FIG. 19. From the graph of FIG. 19, it will be seen that therelated expression, V_(p) =2.47×10⁻² ×D² ×h, is satisfied between thegeometrical average oil feed ratios V_(p) (mm³ /deg) and the plungerdiameter D (mm) and the cam lift h (mm). This related expression meansthat the average oil. feed ratio can be approximately calculated fromthe plunger diameter and cam lift.

As for the types A to J, by the way, the relation between the pistondisplacement V_(s) (l) per one engine cylinder and the geometricalaverage oil feed ratio V_(p) will be next discussed. These relationswill be represented as shown in the graph of FIG. 19, from which it canbe seen that the respective injection pumps are contained in the lowerregion under the straight line K. In other words, it will be said thatany injection pump having such a structure that the average oil feedratio or the delivery pressure is heightened to increase the fuelinjection quantity per the unit angle of its cam does not exist in theupper region over the straight line K. This reason has some connectionwith the use of a centrifugal auto-timer for conducting the control ofthe injection timing in the conventional pumps of the types A to J.Namely, the reason is that each injection pump of the types A to J isset, as shown by the single-dotted chain line in the graph of FIG. 21,so that the delivery pressure of the pump reaches a state almost near tothe limit of the withstanding pressure of the pump itself, when anengine is being operated in the maximum speed region, and the injectiontiming control is conducted by changing the rotating phase of the camshaft with respect to the crank angular phase of the engine gradually,when the engine is in the medium speed region. Accordingly, suchconventional injection pumps could not be used in such a way that in themedium and low speed regions of the engine (corresponding to therevolution number of the cam shaft of 500-900 r.p.m.), the deliverypressure is heightened to be in the region shown by the straight linesL, M and N, thereby to increase the output performance of the engine.

When the injection timing control is conducted in the fuel injectionpump according to the present embodiment, by the way, fuel is injectedin the range of the cam angle θ₂ , as clarified from FIG. 23. At thattime, the cam lift is lower than that in the range of the cam angle θ₁which is in an ordinary injection timing. Therefore, it is possible toprevent the pump delivery pressure from lowering or rising when theinjection timing is advanced.

The relation of this injection timing control and the pump deliverypressure will be described in detail.

A cam diagram which will be obtained by shaping the profile of the cam12 in a cam contour having the dimension shown in FIG. 22 anddetermining the lift thereof at 14 mm, is shown in FIG. 23. Setting thediameter of the plunger 8 at 12 mm, the geometrical average oil feedratio V_(p) obtained in this connection is sought as follows; V_(p)=2.47×10⁻² ×D² ×h=2.47×10⁻² ×12² ×14 ≈49.8 mm³ /deg, and this isdescribed as the point P in the graph of FIG. 20. In the same manner,the geometrical average oil feed ratio V_(p) is found as V_(p) ≈55 anddescribed as the point Q in the graph of FIG. 20, when the plungerdiameter D is 12 and the lift h is 15; V_(p) ≈45 as the point R whenD=12 and h=12.5; V_(p) 26.5 as the point S when D=9.5 and h=12; V_(p)≈24.5 as the point T when D=9.5 and h=11; and V_(p) ≈21.5 as the point Uwhen D=9.5 and h=9.6, respectively. The respective points P to U arearranged in the table of FIG. 24.

Thus, it is understood that if the cam lift is increased with respect tothe plunger diameter, as compared with the table of FIG. 18, the averageoil feed ratios V_(p) will be plotted in the upper portion over thestraight line K, as shown in FIG. 20.

In an in-line injection pump, in general, there is a certain limitationeven in enlargement of the diameter of a plunger, because of arestriction in the arrangement interval of barrels each mounted on theplunger. If the plunger diameter is enlarged, the whole length of theinjection pump will become longer, with its mounting on an engine madedifficult. If the height of a pump housing mounted on an engine exceedsthe upper end of the engine in a large extent, it will be undesirablefrom the angle of the engine's loading property. From this point ofview, there is a limitation on the heightening of a cam lift.Furthermore, there are also limitations in increasing the foundationcircle and cam lift of the cam 12, because the position of fixing boltholes in use for fixing the pump on an engine is restricted.

In order to determine the plunger diameter and cam lift which may beadaptable, in consideration of the planning conditions for theserespective pumps, the average oil feed ratios V_(p) must fall withinsuch a range (this is the obliquely lines portion in FIG. 20) that therelated expression V_(p) =2.47×10⁻² ×D² ×h is satisfied between both therelations of the straight line V_(p1) =22.8 V_(s) +12.8 which connectsthe point Q and point S and the straight line V_(p2) =18.8 V_(s) +10.2which connects the point R and point U, as shown in FIG. 20, and theplunger diameter D and cam lift h can be selected for adaptation so asto satisfy the related expression V_(p) =2.47×10⁻² ×D² ×h, on the basisof V_(p) existing in that range. The sign V_(s) used here expresses apiston displacement (1) per a single cylinder of the engine.

By means of the fuel injection pump according to the invention which hasa plunger diameter and cam lift determined as mentioned above, theengine output can be increased because it acts as a fuel injection pumpwhose delivery pressure is high when the engine is in medium and lowspeed regions, and the engine can be operated under the optimum controlbecause it is kept at the state of the maximum delivery pressure and itsinjection timing is advanced when the engine is in a high speed region.As shown in the graph of FIG. 25, furthermore, the fuel injection pumpof this invention (by the solid line) is composed so that the injectiontime becomes shorter throughout the whole of the engine speed regions,as compared with the aforementioned conventional injection pumps (by thesingle-dotted chain line), and it has various operational effects suchas an improvement in the rate of fuel consumption proportional to theinjection time shortened and a betterment in the exhaust gas performanceof the engine.

In FIG. 21, the straight line L expresses the delivery pressure in thecase of a pump having D=12.5 and h=14 and the straight line N that inthe case of a pump having D=12 and h=13, respectively. In there cases,it is also possible to restrain the delivery pressure while therevolution number of the cam shaft reaches the point M", by conductingthe advancing control. Although the abovementioned descriptions havebeen made as to the pump withstanding pressure of 800 kg/cm², the pumpwithstanding pressure is not limited to that value. The deliverypressure has been made to accord almost with the pump withstandingpressure between the points M'" and M", but the prestroke of the pumpmay be controlled as a matter of course so that the delivery pressure isbelow its withstanding pressure.

On this embodiment, furthermore, the cam has been used having theprofile shown in FIG. 22. If the radius of the cam profile at the pointR₁ is made large, there will be obtained a speed constant diagram in theform of such a trapezoid as shown by the double dotted chain linea-b-c-d in FIG. 23. In the case of this profile, the speed constantbetween the points b-c becomes almost constant (although not shown, thelift curve of this cam must be also changed). If an injection of fuel iscarried out in the range of this cam angle, fuel particles injected intothe combustion chamber will become small and they will be dispersedsatisfactorily in the combustion chamber and burnt effectively here,because the average pressure of this injection is larger. And besides,the selection range for the injection timing (in particular the advancetiming) will be widened, because the average injection pressure islarge.

The second embodiment shown in FIG. 26 to FIG. 30 will be nextdescribed, wherein parts common to the first embodiment are designatedby the same numerals.

A control sleeve 14 is mounted on a plunger 8, and the spherical part281 of the end of an operation lever 28 extended from an operation shaft26 is fitted into a hole 142 formed on the outer peripheral surface 141of the control sleeve. As shown in FIG. 28(a), the plunger 8 has an oilpassage 8a which communicates its upper end face 81 and its peripheralside 812 to each other, and an inclined groove 8d formed on theperipheral side 812 and communicated at one end with the peripheral sideopening of the oil passage 8a, whose position in the longitudinaldirection of the plunger 8 varies gradually. In the control sleeve 14,on the other hand, its downward face is made as an injection beginningface 143, and a control port 14a is formed so as to communicate itsinner peripheral side and its outer peripheral side to each other.Accordingly, the plunger 8 makes a lost motion only by a distance a,while it rises from the home position P₀ shown by a solid line in FIG.28(a). The effective stroke b of the plunger 8 ranges from the positionP₁ [shown by a single dotted chain line in FIG. 28(a)] where theperipheral side opening of the oil passage 8a and the lowermost end ofthe inclined groove 8d reach over the injection beginning face 143 ofthe control sleeve to the position where the inclined groove 8dconfronts the control port 14a of the control sleeve, and the plunger 8can pressurize the fuel in a pressurizing chamber 20 which is above theplunger, while it goes in this effective stroke.

The operation shaft 26 extends along the direction in that otherpressurizing units (not shown) in the injection pump are arranged inrows, and it is attached slidably and rotatably to a housing 2 by way ofbearings (not shown). On one end of the operation shaft 26, as shown inFIG. 27, there are formed a spline part 261 and a part of flange parts262 and 263 continuing thereto, respectively. In the spline part 261,there is fixed an injection timing regulation lever (hereinafter called"the first lever" merely) 51 whose movement in the axial direction B ofthe operation shaft 26 is restricted by a lever restricting member 2a onthe side of the housing 2 and in which the operation shaft 26 isretained for movement in the axial direction B, whereby the operationshaft 26 can be operated so as to be rotated in the axis-rotatingdirection A. In the gap between one pair of the flange parts 262 and263, on the other hand, there is fixed an injection quantity regulationlever (also hereinafter called "the second lever" merely) 52 which ispivotally supported on a pin 50 on the side of the housing 2 and inwhich the operation shaft 26 is retained for rotation around its axis,whereby the operation shaft 26 can be operated so as to be moved in itsaxial direction B. An injection timing control means 53 is connectedwith the turning end of the first lever 51, and a well-known governor 54which acts as an injection quantity control means is connected with theturning end of the second lever 52. The injection timing control means53 used here is composed of an electromagnetic solenoid 56 for turningthe first lever 51 by way of a slider 55 and a control unit 57 forcontrolling the solenoid 56, but it may be composed as a manualoperation type. In addition, the reference numeral 58 represents apotentiometer for measuring the turning displacement of the first lever51 in order to actuate the electromagnetic solenoid 56 with accuracy.Various operating state information sources 59 such as an engine speed,degree of an accelerator pedal trod, temperature of cooling water,temperature of intake air, boost pressure of an air intake system andtemperature of an exhaust gas, are connected to the control unit 57, andthese informations and the information detected by the potentiometer 58will be synthetically calculated to conduct a more accurate control ofthe injection timing.

The operation of the injection pump shown in FIG. 26 will be describedhere. When a Diesel engine (not shown) is driven, a cam shaft 12a beginsto rotate in interlock with the engine so that the plunger 8 is causedto move up and down. With the vertical movement of the plunger 8, thegovernor 54 and control unit 57 are actuated to support the controlsleeve 14 at a given state by way of the operation shaft 26. Now, it isassumed that the control sleeve 14 has been in its home position S₀ [seeFIG. 28(a)], and then the control unit 57 has first supplied its outputcurrent to the electromagnetic solenoid 56 and the first lever 51 hasrotated the operation shaft 26 around its axis, whereby the controlsleeve 14 has moved down to the position S₁ shown in FIG. 28(b). Underthat state, the plunger 8 begins to rise from its home position P₀ andthen moves to the position P₁ where the lowermost end of the inclinedgroove 8d and the peripheral side opening of the oil passage 8a reachover the injection beginning face 143 so that its lost motion distancea₁ becomes relatively small and the injection beginning time istherefore advanced. On the contrary, when the control sleeve 14 moves toan upper position over the home position S₀, the injection beginningtime is delayed. In this regulation of the injection timing, however,the effective stroke b of the plunger does not vary. By virture of theoperation of the governor 54, on the other hand, the second lever 52moves the operation shaft 26 in the axial direction B. Namely, theoperation shaft 26 reaches the position L₁ which is alienated from itshome position L₀ (see FIG. 29) by a slide distance C (see FIG. 30),while it turns the control port 14a which is the injection end on thecontrol sleeve 14 by a given extent. When the plunger 8 begins to risefrom the home position P₀, under that state [see FIG. 28(c)], the lostmotion distance a of the plunger does not vary, as compared with thecase shown in FIG. 28(a). However, the confronting portion of theinclined groove 8d which confronts the control port 14a becomes aportion whose position in the longitudinal direction of the plunger islower [as compared with the case shown in FIG. 28(a)], and the effectivestroke b₁ of the plunger becomes long. On the contrary, when the controlsleeve 14 is turned in the reverse direction to the case shown in FIG.30, the effective stroke becomes short. Thus, the fuel injectionquantity per one stroke of the plunger 8 can be regulated by displacingthe control port 14a of the control sleeve 14.

In the injection pump shown in FIG. 26, namely, the injection timing canbe regulated by rotating a single operation shaft 26 in theaxis-rotating direction A by means of the first lever 51, and theinjection quantity can be also regulated by moving said operation shaft26 in the axial direction B by means of the second lever 52.

Although the operation shaft 26 has slidably meshed with the first lever51 by way of the spline part 261 in the abovementioned embodiment, sucha composition may be alternatively adapted in which a stud key 60 isfixed on the operation shaft 26 and a slidable first lever 51 is mountedthereon, as shown in FIG. 31. Although the electromagnetic solenoid 56has been connected with the first lever 51, furthermore, a hydrauliccylinder (not shown) may be used in place of the solenoid.

The third embodiment will be described with reference to FIGS. 32 and33.

FIG. 32 shows one example of control circuit for a hydraulic pistondriving control device, which utilizes the fuel system of a fuelinjection device. The fuel 62 in a fuel tank 61 is sucked up by a feedpump 63 and filtrated by a fuel filter 64, and then it gets into a fuelinjection pump 65, where the fuel will be supplied in turn from therespective injection plunges for each cylinder to each injection nozzle.A part of the fuel which has come in the injection pump 65 lubricatesthe inside of the pump, and then it is recovered together with theleaked part of fuel from the injection nozzle into the fuel tank 61. Inaddition, the reference numeral 66 represents a governor.

A hydraulic piston 67 for driving a control sleeve which is used for theprestroke control, in this third embodiment, is fixed on the side of theinjection pump 65 opposite to the governor 66, and the fore end thereofis engaged with one end of a lever 69 whose other end is secured on aprestroke control rod 68, as shown in FIG. 33. The prestroke control rod68 is secured on the base of a shift fork which engages with the outerperipheral groove of the aforementioned prestroke control sleeve. Theshift fork is accordingly swinged by way of the lever 69 and the rod 68by moving the piston rod 671 of the piston 67 up and down, and as aresult, the prestroke control sleeve is moved up and down, thereby tochange the prestroke.

In this embodiment, the vertical driving of this piston 67 is carriedout by utilization of fuel in the fuel system. As illustrated in FIG.32, namely, a first bypass 71 which leads to the hydraulic piston 67 byway of a first solenoid valve 70 is provided on the fuel delivery sideof the fuel system, and a second bypass 73 which leads to the hydraulicpiston 67 by way of a second solenoid valve 72 is also provided on thefuel recovery side of the fuel system. The driving of the respectivesolenoid valves 70, 72 is controlled by the signals from a control part75 such as a microcomputer which is operated by the signal obtained froma position sensor 74 provided under the piston rod 671, informing whatstroke position is the piston now in, this is how long is the strokenow, and such signals as a conventional timer has used to determine theinjection timing, for example an engine speed and load, temperature ofoil and water and conveying pressure of fuel. In the case it is requiredto advance the injection timing gradually as the engine speed isgradually increased, it is first judged in accordance with the signalfrom the position sensor 74 whether the prestroke at that time is properor not, and when it is not proper, the second solenoid valve 72 is thenexcited to bring the second bypass 73 into a conducting state in orderthat the injection timing is advanced correspondingly to the enginespeed increased. The fuel in the piston 67 is thereby sucked out and thepiston rod 671 is caused to rise by virture of the elasticity of apiston spring 672, and the rod 68 is turned counterclockwise to push theprestroke control sleeve downwards, and as a result, the prestroke isreduced and the injection timing is advanced. In the case that it isrequired to delay the injection timing, on the contrary, the firstsolenoid valve 70 is excited to bring the first bypass 71 into theconducting state, whereby the fuel is supplied to the piston 67 to lowerthe piston rod 671. Thus, the rod 68 is turned clockwise to push theprestroke control sleeve upward, and as a result, the prestroke is madelarge and the injection timing is delayed. In the control part 75, as amatter of course, there is memorized a correlation between a period oftime when the respective solenoid valves 70 and 72 must continue to beexicted and a value to which the engine speed or load has reached.

Since the driving control device for the prestroke control pistonaccording to this third embodiment untilizes the fuel in the fuelinjection system skillfully, as mentioned above, it is small and compactin size, with no uselessness, and positive in operation.

The fourth embodiment will be next described with reference to FIG. 34.

A cam 75 rotates at the same speed as the rotating speed of an engine,and a tappet roller 76 is in contact therewith to reciprocate a plunger77 provided over the tappet roller with respect to a plunger barrel 78.A control sleeve 79 of a prestroke control device is slidably mounted ona part of the outer periphery of this plunger 77, and one end of acontrol lever 80 is engaged in a slit part formed on the outer peripheryof the control sleeve 79. To the other end of said control lever 80, theactuation rod 811 of a piston 81 is connected, to which piston 81 apressure oil is supplied from a fuel feed pump. As the prestroke controldevice, there can be used various types of known devices.

A distributor 83 is connected between a delivery valve 82 placed on theplunger barrel 78 and an fuel injection nozzle of each cylinder. Thisembodiment is adapted to a two-cylinder engine, and two nozzles 84, 85are connected to the distributor 83. The distributor 83 has a rotor 832with a semi-circular slit formed on the outer periphery, which rotatesin a housing 831, and said rotor 832 will be driven so as to rotate afractional time of the number of the cylinders per one revolution of theengine, this is a one-second revolution in this case. While the cam 75is rotated on time to reciprocate the plunger 77 one time, the rotor 832is accordingly caused to make a half revolution so that high pressurefuel in the barrel 78 is pumped to the nozzle 84 through an injectionpipe 86. With the next one rotation of the cam 75, the rotor 832 iscaused to make further a half revolution, whereby the fuel is pumped tothe other nozzle 85 through another injection pipe 87. During tworevolutions of the engine, or while the piston in the cylinder makesfour strokes of suction, compression, combustion and exhaust, one fuelinjection is carried to in each cylinder. In the case of athree-cylinder engine, accordingly, the fuel injection may besatisfactorily carried out by providing a slit having a one-third lengthof the outer periphery of the rotor 832 on the outer periphery androtating this rotor 832 at a speed which is one-third of the enginespeed.

The function of the prestroke control device which is the most importantpart in this fourth embodiment will be described. Properly speaking, aprestroke control device serves as a timer for regulating a prestroke,thereby to control the fuel injection timing. In this invention, it isused not only as a timer, but also as a means for controlling the fuelinjection pressure. By use of the prestroke control device, namely, theprestroke can be made small at the high speed operation of an engine toadvance the injection timing of fuel, and at the same time, the oil feedratio can be reduced to lower the injection pressure, because theportion of the cam whose rotation angle is small is used, with the camspeed lowered, in that fuel injection after all.

The driving of the control sleeve 79 in the prestroke control device iscarried out in relation to the detected speed of the engine or thedetected oil-feed pressure of the feed pump. In the illustratedembodiment, the driving of the control sleeve 79 is carried out bysupplying to the piston 81 a part of the pressure oil to be fed from thefeed pump to the plunger 77. Namely, when the engine gets to operate ata high speed, the oil feed pressure for the fuel coming from the feedpump is increased and the piston 81 is pushed up, and as a result, theactuation rod 811 turns the lever 80 clockwise, thereby to push down thecontrol sleeve 79. Thus, the distance between the position of a fuelfeed port provided on the control sleeve 79 and the position of a spillport 31 of the plunger 77 when it is at the bottom dead center, is madeshort and the prestroke is reduced, whereby the injection timing isadvanced and the oil feed ratio is reduced, with the injection pressuredlowered, as mentioned above.

According to the fourth embodiment in which a prestroke control deviceis provided on the injection pump of a fuel injection and distributiondevice and its prestroke is controlled in accordance with the revolutionspeed of an engine or the oil feed pressure of a feed pump by means ofthis prestroke control device, it is therefore possible to restrain anundesirable increase in the injection pressure at the high speedoperation of the engine, and besides to prevent the generation ofsecondary injection or cavitation erosion and to improve the durabilityof the device.

Referring to FIGS. 35 to 37, the fifth embodiment will be described. Allthe parts other than a cam 89 and a delivery valve 90 mentioned below,are the same in the structure and contour of these shown in FIG. 4 andFIG. 26, and their description will be omitted because these figures canbe adapted to this embodiment.

FIG. 35 shows a cam 89. In this cam 89, its part ranging from 90° to270° in the drawing is a cam part 89a similar to that shown in FIGS. 4and 26 and its part ranging before and after 0° is an auxiliary cam part89b newly provided. FIG. 36(A) and (B) show a delivery valve 90. On thecollar part 90b formed under the valve part 90a thereof, there isprovided a notch part 91 which is called "Angleichung cut". Even whenthe injection quantity is small, for instance at the light loadedoperation of an engine, fuel will be injected through the gap of thenotch part 91 if the valve part 90a opens slightly a valve seat providedin a delivery valve holder 6. Although the portion from the valve part90a to the lower end of the collar part 90b is set as the suction strokeof the delivery valve 90, the valve 90 is likely to make no displacementover said stroke at the light loaded operation, and said notch part 91is therefore provided to prevent this no displacement of the valve.

Just after the cam angle goes over 90° as shown in FIG. 37, the cam part89a is brought into rolling contact with said roller 25a so that the camlift becomes gradually large and the plunger 8 is pushed up. When theplunger 8 begins to reach the prestroke position P₁, the delivery valve90 becomes opened so that the pumping of fuel is started. And then, theinclined groove 8d confronts the control port 14a and the fuel deliveryis completed. After that time, the cam lift is further increasing and itbecomes the maximum when the cam angle is about 180°. When the cam anglegoes over 180°, the plunger 8 begins to fall so as to have a function ofreturning the fuel from the high pressure system. In the high pressuresystem, at that time, its residual pressure drops quickly, with acavitation caused. When the rolling contact position of the cam 89 whereit rotates into contact with the roller 25a is transferred from the campart 89a to the auxiliary cam part 89b, the cam lift is increased againand the plunger 8 goes over the prestroke position. As a naturalconsequence, the delivery valve 90 is caused to open so that the fuel ispumped out. The cam stroke becomes the maximum when the cam angle is atthe 020 position, and it is lowering gradually from that state andbecomes the minimum when the cam angle is at the 90° position. Thisminimum stroke of the cam serves merely to send out a very slightquantity of fuel and is useless for the actual fuel injection, but itcan increase the residual pressure in the high pressure system to avoidthe cavitation positively. Accordingly, when the cam lift is increasedagain to act the injecting operation, a smooth injection of fuel withgood timing can be carried out without any trouble. (The double dottedchain line in the graph represents a change in cam lift obtained by acam with a conventional cam contour.)

According to the fifth embodiment, as have been explained in the above,an auxiliary cam part is provided on a cam in order to raise theresidual pressure in the high pressure system during the fuel pumpingstroke once, whereby various effects can be obtained, for example ofimproving such disadvantages as an actual injection lag and intermittentinjection, in particular at the low speed operation of engine, betteringthe starting performance of engine and the ratio of fuel consumption,and stabilizing the engine idling.

The sixth embodiment will be described with reference to FIG. 38 to FIG.40. The same members as in the aforementioned first embodiment will beomitted in description by marking with the same reference numerals.

The reference numeral 14 represents a cylindrical fuel control sleevemounted on the outer periphery of a plunger 8 in a fuel chamber 15 so asto be freely slidable in the direction of its axis and rotatable aroundthere; 92 is an arcuate guide groove cut on the outer peripheral surfaceof the sleeve 14 in a plane intersecting at a right angle with the axisof the plunger 8; 26 is an injection timing control shaft whose axis iscontained in a plane perpendicular to the axis of said plunger 8; 28 isan injection timing control arm protruding from the control shaft 26, inwhich the spherical part 94 on its fore end is inserted in said guidegroove 92; 96 is a gear provided on the outer peripheral surface of saidcontrol sleeve 14 opposite to said guide groove 92 along nearly the halfof its circumference; and 98 is a rack member meshing with said gear 96,which is, in the device shown in the drawings, a cylindrical rack memberformed by rolling a rack tooth profile around an axis perpendicular tothe axis of the plunger 8, or may be a well-known rack rod. Thereference numeral 100 represents a plunger rotation preventing sleevemounted on the lower end portion of the plunger 8, in which the flangepart of its upper end is fixed on a housing 2 by knock pins 102, and theangular sectional part of its lower end is mounted on the angular part83 on the plunger 8 corresponding thereto, and so a result, the plunger8 is permitted to displace freely in its axial direction, but can not berotated around the axis. In addition, this plunger rotation preventingsleeve 100 may be fixed, as to its rotating direction, onto a barrel 4,or may be formed as one body with the barrel 4 and indirectly fixed onthe housing 2 by bolts 104.

Since the sixth embodiment has such a composition as mentioned above,the fuel feed quantity can be regulated by moving the rack member 98 inits axial direction to turn the control sleeve 14 around the axis of theplunger 8 and change the related position of control ports 14a and alongitudinal groove 8c that is a part of a control groove. And,furthermore, the related position of the control ports 14a and thecontrol groove in the direction of the cam lift can be changed or theinjection timing can be regualted by turning the control shaft 26 aroundits axis to displace the control sleeve 14 in the axial direction of theplunger 8 by way of the control arm 28.

In order to match uniformly the fuel injection quantities of theinjection pump for a plurality of cylinders, furthermore, according tothis sixth embodiment, said rack member 98 is screw-engaged on a screwshaft 106. By the relative turning of the rack member 98 to the screwshaft 106 in a proper direction, the rack member 98 can be thereforemoved in its axial direction along the screw shaft 106, and in otherwords, the control sleeve 14 can be moved to a desired related positionaround the plunger 8. After completion of this adjustment, the rackmember 98 is fixed to the screw shaft 106 by means of fixing nuts 108.As a result, the fuel injection quantity of the injection pump can beadvantageously regulatd easily and quickly so as to be matched uniformlyin every cylinder. In the aforementioned embodiment, in addition, thecontrol groove has been provided on the plunger 8 and the control portscooperating therewith has been provided on the control sleeve 14, but itmay be so composed likely to the aforementioned well-known device that acontrol groove inclined with respect to the plunger axis is provided onthe side of the control sleeve 14 and control ports communicated to theoil passage 8a are opened on the outer peripheral surface of the plunger8.

The seventh embodiment will be described here with reference to FIG. 38to FIG. 41.

Although the barrel 4 has been removably mounted on the upper end of thehousing 2 and the upper end flange part of the plunger rotationpreventing sleeve 100 has been fixed on the housing 2 by the knock pins102 in the aforementioned sixth embodiment, the seventh embodimentdiffers from the sixth embodiment only on the point of view in which itis so composed that the upper end flange part of a plunger rotationpreventing sleeve 100 may be fixed on the barrel 4, not on the housing2, or that sleeve 100 may be formed as one body with the barrel 4 so asto be fixed together with the barrel 4 directly onto the housing 2 bymeans of bolts 104. The other composition of the seventh embodiment isthe same as the sixth embodiment. In order to match uniformly the fuelinjection quantities of the injection pump for a plurality of cylinders,the fine regulation of these injection quantities is carried out byturning the barrel 4 and the plunger 8 as one body around the plungeraxis in a proper direction to change their relative related position tothe control sleeve 14, and in other words, to change the relativeposition of the control ports 14a to the control groove, before thebarrel 4 is fixed to the housing 2 by the bolts 104. To this end, asshown in FIG. 41, the seventh embodiment is composed so that bolt holes110 on the barrel 4, which cooperate with the bolts 104, are formed aslong holes, thereby to enable the barrel 4 to turn around the plungeraxis. As a result, there is an advantage of finely regulating theinjection quantities of the fuel injection pump for every cylinderquickly and easily to match them to one another.

Since the rack member 98 is also screw-engaged on the screw shaft 106 inthe same way as the sixth embodiment, the rack member 98 can be moved inthe axial direction of the screw shaft by turning the rack member 98 ina proper direction with respect to the screw shaft, and in other words,the control sleeve 14 can be moved to a desired related position aroundthe plunger 8, thereby to conduct the fine regulation of the injectionquantity secondarily. As a matter of course, said rack member 98 isfixed at a given position by the fixing nuts 108 similarly to the sixthembodiment.

The eighth embodiment will be next described below with reference toFIG. 42 to FIG. 45.

The reference numeral 2 represents a housing of a fuel injection pump; 4is a barrel detachably mounted on the upper end of said housing; 20 is afuel pressurizing chamber formed in the barrel 4; 7a is a fuel deliveryvalve contained in a delivery valve holder 6 screw-engaged in the upperend of said barrel 4, which is preloaded by a spring 7b to block up saidpressurizing chamber 20; 6a is a delivery passage formed in saiddelivery valve holder 6 and communicated to a fuel injection nozzlethrough a fuel injection pipe (not shown); and 8 is a plunger slidablymounted in the housing 2 by way of said barrel 4, whose upper end facefaces to said pressurizing chamber 20 and whose end part is in contactwith a cam 12 by way of a cam holder (tappet) 25 and a roller 25a. Thereference numeral 12a represents a cam shaft which is driven by anengine (not shown); 10 is a spring which forces always said cam holder25 to the side of the cam 25; and 15 is a fuel chamber formed so as tosurround said plunger 8, to which fuel is always supplied by means of afeed pump (not shown) during the operation of the engine. The referencenumeral 14 represents a cylindrical fuel control sleeve mounted on theouter periphery of the plunger 8 in the fuel chamber 15 so as to befreely slidable in the axial direction of the plunger and rotatablearound there; 92 is an arcuate guide groove cut on the outer peripheralsurface of the sleeve 14 in a plane intersecting at a right angle withthe axis of the plunger 8; 26 is an injection timing control shaft whoseaxis is contained in a plane perpendicular to the axis of said plunger8; 28 is an injection timing control arm protruded from the controlshaft 26, in which the spherical part 94 on its fore end is inserted insaid guide groove 92; 96 is a gear provided on the outer pheripheralsurface of said control sleeve 14 opposite to said guide groove 92 alongnearly the half of its circumference; 112 is a rack rod meshing withsaid gear 96; and 8a is an oil passage in the plunger, in which one endthereof is opened into said pressurizing chamber 20 and the other endthereof is communicated with a control groove 8c, 8d cut on the outerperipheral surface of the plunger contacting with said control sleeve14, the control groove being composed of a portion 8d inclined withrespect to the plunger axis and a portion 8c extending in the axialdirection of the plunger and shaped in the letter λ (lambda) on thewhole. The reference numeral 14a represents control ports perforated insaid control sleeve 14 in the radial direction and cooperating with saidcontrol groove; and 114 represents a hollow tube-shaped plunger guidemounted on the lower end portion of the plunger 8, in which the angularsectional part 116 on its lower end is fitted on the angular part 8e onthe plunger 8 corresponding thereto, and as a result, the plunger 8 ispermitted to displace freely in its axial direction with respect to thebarrel 4 and plunger guide 114, but can not be relatively rotated aroundits axis with respect to the plunger guide 114. On the outercircumferential portion of the upper end flange of the plunger guide114, as illustrated in detail in FIG. 45, there is provided a projection120 with an axial engagement groove 118. In the wall surface of thehousing 2 which is opposited to the projection 120, on the other hand,there is rotatably mounted a regulation member 124 having an eccentricpin 122 to be engaged in said engagement groove 118, and the regulationmember 124 is devised so that a lock nut 128 is screw-engaged with itsscrew part 126 protruded to the outside of the housing 2.

When the respective members of the fuel pump are in the illustratedpositions, in the aforementioned device, the control ports 14a and thecontrol groove 8c, 8d are not in communication with each other and thelower ends of the control groove are protruded downward from the lowerend face of the control sleeve 14 so as to be opened into the fuelchamber 15, and as a result, the pressurizing chamber 20 and the fuelchamber 15 are kept in communication with each other. When the cam shaft12a is now rotated by the engine from this state and the plunger 8 ispushed upward by way of the roller 25a by the cam 12, the lower ends ofsaid control groove are closed by the control sleeve 14 so that thecommunicatoin between the pressurizing chamber 20 and the fuel chamber15 is interrupted because the communication between the inclined portionfo the control groove and the control port 14a is kept interrupted. Thefuel in the pressurizing chamber is therefore pressurized with the riseof the plunger 8, and when its pressure exceeds a set value, thedelivery valve 7a is opened whereby the fuel is fed from the deliverypassage 6a to the injection nozzle of the engine. When the plunger 8rises further so that the inclined groove portion 8d of the controlgroove is brought into communication with the control port 14a of thecontrol sleeve 14, the pressurizing chamber 20 communicates to the fuelchamber 15 again and the fuel injection is finished. Thus, the upper endof the axial portion 8c of said control groove is protruded upward fromthe upper end face of the control sleeve 14 to communicate thepressurizing chamber 20 and fuel chamber 15 directly, thereby to preventthe two-stage injection of fuel positively. By moving the rack rod 112in its axial direction and turning the control sleeve 14 around the axisof the plunger 8 to change the related position of the control port 14aand control groove, thereafter, the fuel feed quantity is increased orreduced. By turning the control shaft 26 around its axis to displace thecontrol sleeve 14 in the axial direction of the plunger 8 by way of thecontrol arm 28, the related position of the control port 14a and controlgroove in the direction of the cam lift is changed, or the injectiontiming is regulated. In addition, said rack rod 112 and control shaft 26each are driven artifically by an engine control device (not shown) suchas an accelerator, governor or timer in the case of a motor vehicle, orby a proper actuator.

According to this eighth embodiment, the lock nut 128 is relaxed and theregulation member 124 is turned by use of a tool such as a screw driver,when the injection quantities of the injection pump for a plurality ofcylinders are matched uniformly. Then, the plunger guide 114 is turnedtogether with the plunger 8 around the plunger axis in a properdirection, owing to the co-operation of the eccentric pin 122 and theengagement groove 118 so that the relative related position of theplunger to the control sleeve 14 is changed, and in other words, therelative position of the control port 14a to the control groove ischanged, thereby to conduct the fine regulation of the injectionquantity of the fuel injection pump for each cylinder. Thus, theinjection quantities of the injection pump for all the cylinders arematched with one another and the lock nuts 128 of the respectiveregulation members 124 each are then tightened to fix each regulationmember 124 onto the housing 2. At that time, the plunger guides 114, andtherefore the plungers 8, each are accurately related to the controlsleeve 14 confronting thereto, by way of the eccentric pin 122 andengagement groove 118. As a result, there is an advantage of finelyregulating the injection quantities of the fuel injection pump for everycylinder quickly and easily to match them uniformly. In theaforementioned embodiment, the control groove has been provided on theplunger 8 and the control ports 14a cooperating therewith have beenprovided on the control sleeve 14, but it may be so composed that acontrol groove inclined with respect to the axis of the plunger isprovided on the side of the control sleeve 14 and control portscommunicating with the oil passage 8a are opened on the outer peripheralsurface of the plunger 8. Although a combination of the eccentric pin122 and the engagement groove 118 has been used in the aforementionedembodiment, it is obvious that a positive cam device composed of a camand a cam groove, having the same effects viewed at the angle of themechanics, can be equally substituted therefor.

Referring to FIG. 46 to FIG. 49, the ninth embodiment will be described.Explaining only parts different in composition from the eighthembodiment, a fuel chamber 15 formed so as to surround a plunger 8 isdivided into an oil feed chamber 15a and an oil discharge chamber 15b,and the oil feed chamber 15a is always supplied with fuel by means of afeed pump (not shown) during the operation of an engine and the oildischarge chamber 15b is communicated with the suction side of the feedpump or a fuel tank. A somewhat triangular control groove 130 is cut onthe outer peripheral surface of the plunger which contacts with acontrol sleeve 14, and one end of an oil passage 8a in the plunger isopened into a pressurizing chamber 20 and the other end thereof iscommunicated with the control groove 130. Said control groove 130 has anupper side portion inclined with respect to the plunger axis. Thereference numeral 131 represents an oil feed port in which one endthereof is opened to the outer peripheral surface of the plunger 8 andthe other end thereof is communicated with said oil passage 8a, and inthis embodiment, said oil feed port 131 is arranged with an angleinterval of about 180° from said control groove 130 around the plungeraxis and opened somewhat below the bottom side of the control groove130, as clearly shown in FIG. 47 and FIG. 48. The reference numeral 132represents an oil discharge port perforated in the radial direction insaid control sleeve 14, which co-operates with said control groove 130.And, the reference numeral 134 represents partition plate protrudedlyprovided in the radial direction in said barrel 4; and 136 representspartition plates protrudedly provided in the housing 2 toward the barrel4. All of these partition plates serve to divide said fuel chamber 15into the oil feed chamber 15a and the oil discharge chamber 15b.

As for the aforementioned device, the operation mode of the fuel pumpwill be described in detail by making reference to FIG. 49(A) to FIG.49(E) mainly. In all FIGS. 49(A) to 49(E), the inner peripheral surfaceof the control sleeve 14 and the outer peripheral surface of the plunger8 cooperating therewith are shown as they are developed and overlappedto each other. When both of them are at first in the position shown inFIG. 49(A), the oil discharge port 132 and control groove 130 are not incommunication with each other and the lower end of the oil feed port 131gets downward out of the lower end face of the control sleeve 14 andopens to the oil feed chamber 15a of the fuel chamber 15, and as aresult, the pressurizing chamber 20 and the oil feed chamber 15a arecommunicated with each other. If the cam shaft 12a is now rotated by theengine from this state and the plunger 8 is pushed upward by way of theroller 25a by the cam 12 so as to come to the position shown in FIG.49(B), the lower end of said oil feed port 131 is closed by the controlsleeve 14 and the communication between the inclined portion of thecontrol groove 130 and the oil discharge port 132 is kept interrupted sothat the communication between the pressurizing chamber 20 and the fuelchamber 15, or both the oil feed chamber 15a and oil discharge chamber15b is interrupted. Accordingly, the fuel in the pressurizing chamber 20is pressurized with the rising of the plunger 8, and when its pressureexceeds a set value, a delivery value 7a is opened, whereby the fuel isfed from the delivery passage 6a to the injection nozzle of the engine.When the plunger 8 rises further and reaches the position shown in FIG.49(C), the inclined oblique portion of the control groove 130 iscommunicated with the oil discharge port 132 of the control sleeve 14 sothat the pressurizing chamber 20 is communicated with the oil dischargechamber 15b of the fuel chamber 15, thereby to complete the fuelinjection. Then, the upper end of the axial portion of said controlgroove 130 reaches the position of FIG. 49(E) from the position of FIG.49(D) and gets upward out of the upper end face of the control sleeve 14whereby the pressurizing chamber 20 and fuel chamber 15 are directlycommunicated with each other to prevent the two-stage injection of fuelpositively. In addition, the fuel feed quantity is increased ordecreased by moving a rack rod 112 in its axial direction to turn thecontrol sleeve 14 around the axis of the plunger 8 so that the relatedposition of the oil discharge port 132 and the control groove 130 ischanged. And, the related position of the oil discharge port 131 and thecontrol groove 130 in the direction of the cam lift is changed, andnamely the injection timing is regulated, by turning a control shaft 26around its axis so that the control sleeve 14 is displaced in the axialdirection of the plunger 8 by way of a control arm 28.

In the abovementioned fuel pump, the fuel whose temperature is risedthrough its compression, after the fuel injection is completed, iscaused to flow out of the pressurizing chamber 20 into the oil dischargechamber 15b and then returned to the suction side of the feed pump or afuel tank (not shown). Accordingly, this fuel pump can restrain thetemperature rise of the fuel effectively in comparison with theaforementioned pump devices already proposed in which the fuel chamber15 is not divided into the oil feed chamber 15a and oil dischargechamber 15b, and can effectively prevent undesirable variations in theinjection characteristics caused by the rise of the fuel temperature. Asclearly understood from the above description, said partition plates 134and 136 which divide the fuel chamber 15 into the oil feed chamber 15aand oil discharge chamber 15b are enough only to perform a function ofpreventing the mixing of the fuel coming into the pressurizing chamber20 and the high temperature fuel flowing out of the pressurizing chamber20 after completion of the fuel injection in some extent, and must notkeep a strict oil-tightness between them. In addition, the angularinterval between the control groove 130 and oil feed port 131 providedon the outer peripheral surface of the plunger 8 around the plunger axisis not limited to an angle of about 180° shown in the drawings, and itmay be 90° or may be as large as 60°. In short, a proper angularinterval may be selected so as to obtain a well-balanced state with saidpartition plates 134 and 136 generally demarcating the oil feed chamber15a and the oil discharge chamber 15b, and in particular with the formerpartition plates 134.

The tenth embodiment will be described here with reference to FIGS. 50and 51.

The tenth embodiment is different from the eighth embodiment at theviewpoint that the vertical movement of the control sleeve 14 iscontrolled by the control shaft 26 and the turning thereof by the rackrod 112 in the eighth embodiment, but the tenth embodiment is socomposed that both the vertical movement and turning of a control sleeve14 are controlled by only one control shaft member 142. The referencenumeral 138 represents a L-shaped flow regulation pin whose one end issecured on the outer peripheral surface of the control sleeve 14, and onits vertical pin 138a extended in the direction of the plunger axis,there is secured an injection timing regulation pin 140 which extends soas to intersect the plunger axis at a right angle. The reference numeral142 represents generally a control shaft member which cooperates withsaid flow regulation pin 138 and injection timing regulation pin 140,and this control shaft member 142 is composed of an injection quantitycontrol member 144 connected with a proper actuator such as a linearsolenoid (not shown) for giving a straight motion so as to be displacedin the direction of the arrows A and A', and an injection timing controlmember 146 engaged with the injection quantity control member 144telescopically in the axial direction and connected with a properactuator such as a rotary solenoid (not shown) so that said injectionquantity control member 144 is turned around its axis by the turning ofthe injection timing control member itself around the axis, as shown indetail in FIG. 51. The reference numeral 148 represents an engagementmember which is protrudedly provided on the angular sectional portion ofsaid injection quantity control member 144 toward said control sleeve14, and this engagement member 148 has a first groove 150 which engagesslidably with the vertical pin 138a of the flow regulation pin 138, anda second groove 152 which engages slidably with said injection timingregulation pin 140.

According to this tenth embodiment which has the aforementionedcomposition, the movement of the injection quantity control member 144in its axial direction, for example in the direction of the arrow A inFIG. 51 by means of the actuator causes the engagement member 148 todisplace in the direction A so that by virtue of the cooperation of itsfirst groove 150 and the vertical pin 138a, the flow regulation pin 138and therefore the control sleeve 14 are turned clockwise around the axisof the plunger 8 and the related position of a control port 14a and acontrol groove 154 is changed, whereby the fuel feed quantity isregulated. By turning the injection timing control member 146 around itsaxis by means of the aforementioned proper actuator such as a rotarysolenoid, the engagement member 148 is turned around the axis of thecontrol shaft member 142 so that by virtue of the cooperation of thesecond groove 152 and the injection timing regulation pin 140, thecontrol sleeve 14 is displaced in the axial direction of the plunger 8and the related position of the control port 14a and control groove 154in the direction of the cam lift is changed, whereby the injectiontiming is thus regulated. Since the member for turning the controlsleeve 14 around its axis to carry out the control of the fuel injectionquantity and the member for displacing the control sleeve 14 in theaxial direction to carry out the control of the injection timing arearranged in one side of the sleeve 14 in the radial direction, accordingto this composition, the device of this embodiment has advantages ofbeing simple in structure as compared with a conventional device and ofreducing the lateral size in the portion of the control sleeve 14.Furthermore, the matching of the injection timings of the injection pumpfor a plurality of cylinders can be carried out by (i) adjusting a shimon the clamping face between the barrel 4 and the housing 2 and (ii)adjusting a shim between the cam holder (tappet) 25 and the lower end ifthe plunger 8. In addition, the aforementioned embodiment may becomposed so that a control groove inclined with respect to the plungeraxis is provided on the side of the control sleeve 14 and a control portcommunicating with the oil passage 8a is opened on the outer peripheralsurface of the plunger 8, although the control groove 154 has beenprovided on the plunger 8 and the control port 14a cooperating therewithhas been provided on the control sleeve 14.

Describing a modification of the aforementioned tenth embodiment withreference to FIG. 52, the reference numeral 144' represents an injectionquantity control member having a circular cross-section, on which anengagement member 148' with a first groove 150' and a second grove 152'is mounted and fixed by an adjustment bolt 156 and a nut 158. The fuelinjection quantity can be therefore regulated by displacing theinjection quantity control member 144' in the axial direction in thesame way as the tenth embodiment to rotate the control sleeve 14, andthe injection timing can be regulated by turning the injection quantitycontrol member around its axis to move the control sleeve 14 up or down.As to the initial matching of the injection pump for a plurality ofcylinders, furthermore, it is possible to match the injection quantitiesby relaxing said nut 158 to move the engagement member 148' in the axialdirection and the injection timings by adjusting the angular position ofthe engagement member 148' around its axis, respectively.

The eleventh embodiment will be described below.

In the actual pumping of fuel, the so-called preflow is easily causedand the pressure rising is not sharp. The preflow occurs from the causethat before the opening of an oil passage on the side of the peripheralsurface of a plunger is closed completely by a control sleeve, theopening of the oil passage is gradually constricted. This is owing tothe circular form of said opening. Fuel is therefore pumped outgradually and as a result, fuel whose pressure does not reach a giveninjection pressure still is leaked from an injection nozzle V, withdisadvantages such as the generation of smoke and the worsening of theratio of fuel consumption.

This eleventh embodiment has been achieved by paying attentions to theaforementioned facts and its object is to provide a fuel injection pumpin which a pumping beginning relief part is connected to the opening ofan oil feed port on the plunger periphery, whereby the preflow can berestrained and the pressure rising can be sharpened to prevent thegeneration of smoke and improve the ratio of fuel consumption.

The eleventh embodiment will be now described with reference to FIG. 53and FIG. 54. This eleventh embodiment is characterized only in thecomposition of a plunger, but all the other portions are common incomposition to these of the aforementioned first to tenth embodimentseach and so the description about the common portions will be omitted.

A plunger 8 has an oil passage 8a provided therein in which openingsopening at its upper end face and at a portion of its peripheral surfaceare communicated with each other. An inclined groove 8d provided bent onthe peripheral surface of the plunger 8 is communicated to the opening8b of this oil passage 8a on the side of the peripheral surface of theplunger 8. A pumping beginning relief part 160 is further communicatedto the opening 8b of the oil passage 8a on the side of the plungerperiphery. This pumping beginning relief part 160 is a groove providedalong the peripheral surface of the plunger 8, as shown in FIGS. 53 and54, and the size of its width is required to be at least equal to orlarger than the opening 8b of the oil passage 8a. In addition, the loweredge of the pumping beginning relief part 160 must be equal to orsmaller than the lower edge of said opening.

When the opening 8b of the oil passage 8a on the side of the peripheralsurface of the plunger 8 is thus positioned below the lower end face ofa control sleeve 14, fuel is permitted to enter from there into a barrel4. The plunger 8 rises and passes the lower end face of the controlsleeve 14 from the upper end of said opening 8b. At the same time, thepumping beginning relief part 160 confronts the lower end face of thecontrol sleeve 14, and the introduction of fuel continues because theeffective area of the oil passage 8a is not reduced. The pressure of thefuel in the barrel 4 does not reach a given pressure and its pumpinginto the injection nozzle V is not started until the lower edge of theopening 8b passes the lower end face of the control sleeve 14 and thelower edge of the pumping beginning relief part 160 also passes thelower end face of the control sleeve 14. Since the pumping beginningrelief part 160 and the opening 8b are communicated with each other,namely, the pumping motion is carried out by the complete closing of thepumping beginning relief part 160. In other words, the effective area ofthe opening 8b of the oil passage 8a is expanded by the pumpingbeginning relief part 160, and when the lower edge of the pumpingbeginning relief part 160 positions above from the lower end face of thecontrol sleeve 14, this effective area becomes zero at a stroke.Accordingly, the preflow quantity of fuel can be reduced and thepressure rising can be sharpened, with no time required for increasingthe injection pressure.

In FIG. 57, the solid line represents the pump characteristic resultedfrom the structure of the aforementioned eleventh embodiment and thedotted line represents that of a conventional structure, respectively.The designation S in the drawing represents a prestroke position. Thepump characteristic curve in the aforementioned embodiment until theeffective area of the oil passage 8a becomes zero is sharp, but that ofthe conventional structure is gentle. As to the oil feed ratio of fuel,therefore, its rise leading to a given ratio is sharp in theaforementioned embodiment and mild in the conventional structure.

FIG. 55 and FIG. 56 show another modification of this embodiment. Themodification is the same as the aforementioned embodiment in such apoint that the oil passage 8a and inclined groove 8d are provided in theplunger 8, but it is composed so that a pumping beginning relief part160a is cut flat on the peripheral surface of a plunger 8. It is amatter of course that this pumping beginning relief part 160a iscommunicated with the opening 8b of the oil passage 8a and its width inthe vertical direction is required to be at least equal to or largerthan the opening. The lower edge of the pumping beginning relief part160a must be equal to or smaller than the lower edge of the opening 8b.Thus, the pumping beginning relief part 160a can obtain the quite sameoperational effects as the aforementioned embodiment.

The control of the control sleeve 14 in the aforementioned embodimenthas been based on the system of the second embodiment shown in FIG. 26,but it may be based on an alternative system.

According to this embodiment which has been described in the above, thepumping beginning relief part provided on the peripheral surface of theplunger is communicated with the oil passage opening provided on theperipheral surface of the plunger, and this pumping beginning reliefpart can therefore serves to reduce the preflow quantity of fuel and toprevent the generation of smoke and improve the rate of fuelconsumption. Furthermore, a fuel injection pump can be thereforeprovided which is relatively simple in structure, with no bad influenceupon the cost.

The twelfth embodiment shown in FIG. 58 is a modification of the eighthembodiment shown in FIG. 42 to FIG. 45, wherein a regulation member 28with an arm 28a protruded therefrom has a sloping surface 28b protrudedoutward in the radial direction, and a press rod 203 is contacted underpressure with said sloping surface 28b by means of a spring 202 in aspring case 201 detachably screw-engaged on a housing 2. The referencenumeral 204 represents a hollow plug detachably screwed on the housing 2in access to said rack rod 112; and 205 represents a settling shaftrotatably and oil-tightly inserted in said hollow plug, wherein aneccentric pin 206 which contacts with the lower end face of said controlsleeve 14 is provided on the inward end of the settling shaft in thehousing, and a groove 207 to which a tool such as a screw driver is tobe fitted is provided on the outward end thereof from the housing.

In the abovementioned fuel injection pump device, it is required tomatch the fuel injection timings of the injection pump for a pluralityof cylinders uniformly after its manufacture and assemblage arecompleted, but before it is fixed on an actual engine. The settling ofthe injection timings will be carried out as follows:

(1) The spring case 201 is at first screw-engaged to the housing 2, witha fixing bolt or screw 208 of the injection timing regulation member 28relaxed, and the fore end of the press rod 203 is elastically engaged tothe sloping surface 28b of said regulation member 28.

(2) In the housing 2, on the other hand, the hollow plug 204 isscrew-engaged and the eccentric pin 206 of the settling shaft 205rotatably supported in the plug is kept contacted with the lower endface of the control sleeve 14. Under that state, the regulation member28 is biased clockwise in FIG. 58 by way of the press rod 203, by virtueof the force of the spring 202, and as a result, the control sleeve 14is elastically contacted under pressure to the eccentric pin 206 by wayof the arm 28a and its spherical part 94, with no play caused.

(3) The injection starting time of the fuel injection pump for eachcylinder is then measured, while the cam shaft 12a is driven. To theinjection pump whose injection starting time is out of a standard, atool such as a screw driver is applied to the groove 207 of the settlingshaft 205 to rotate the settling shaft 205 so that the control sleeve 14is caused to displace in the axial direction of the plunger 8 by virtueof the eccentric rotation of the eccentric pin 206 and the injectionstarting time is settled at a reference value, and then a lock nut 209is tightened to fix the settling shaft 205. In the same way, the fuelinjection timings of the injection pump for all the cylinders are set soas to be matched uniformly.

(4) Thereafter, a blind plug 210 for the working hole provided adjacentto the spring case 201 is removed and the bolt or screw 208 is tightenedto fix the injection timing regulation member 28 on the control shaft26. As a result, the fuel injection timings of the injection pump forall the cylinders are matched uniformly.

(5) After completion of the aforementioned work, the spring case 201 andhollow plug 204 are taken out of the housing 2, and the blind plugs arescrew-engaged into the screw holes of the housing 2, and all the fuelinjection timing-settling work is thus completed.

According to the aforementioned working process, it is advantageouslypossible, in the case of the fuel injection pump for a multi-cylinderengine, to regulate finely the fuel injection timings for every cylinderand to match and settle them accurately, quickly and easily.

Although a temporary settling means for finely displacing the controlsleeve 14 in the axial direction of the plunger 8 has been made up ofthe settling shaft 205 having the eccentric pin 206 which cooperateswith the lower end face of the control sleeve 14 in the aforementionedembodiment, it may be composed that a rack tooth profile having threadsin the lateral direction is cut in a plane crossing the control port14a, on the outer peripheral surface of the control sleeve 14 which doesnot interfere with the rack rod 112 and the regulation member 28, and asettling shaft with a pinion meshing with the rack teeth is rotatablysupported on the housing 2, similarly to said settling shaft 205 withthe eccentric pin 206, wherein the settling shaft is rotated from theoutside of the housing in the same way, thereby to regulate finely therelative position of the control sleeve 14 and plunger 8 in the verticaldirection by way of the pinion and rack teeth.

The thirteenth embodiment shown in FIG. 59 is a modification of theeighth embodiment shown in FIG. 42 to FIG. 45, which represents a methodfor carrying out the settling of injection timings, because it isrequired, after completion of the manufacture and assemblage of the fuelinjection pump described in the eighth embodiment, to match the fuelinjection timings of this injection pump for a plurality of cylindersuniformly before its mounting onto an actual engine.

(1) After the delivery valve holder 6 is first taken off and thedelivery valve 7a and spring 7b are removed, the delivery valve holderis attached to the barrel 4 again. An air manometer 170 is thenconnected to the open end of the delivery passage 6a by a fitting 172.The air manometer 170 is connected to a proper compressed air source 176by way of a pressure reducing valve 174.

(2) On the other hand, a sealing plug 182 screw-engaged with aregulating opening 180 opened on the wall portion of the housing 2 whichconfronts said injection timing control member 178 is removed to openthe opening 180.

(3) When the pressure reducing valve 174 is opened in the aforementionedstate, the compressed air which has been regulated in pressure ispermitted to pass through the air manometer 170 and flow into the fuelchamber 15 through the delivery passage 6a, the pressurizing chamber 20,the oil passage 8a and the control groove comprising the longitudinalgroove 8c and inclined groove 8d, and further flow out to theatmosphere. (At that time, the control sleeve 14 shall be at theposition shown in FIG. 42, FIG. 43 and FIG. 44.) In this case, theindicator 184 of the air manometer 170 is in a floating position asshown in the drawing owing to the air flow.

(4) Then, a proper tool is inserted from the regulating opening 180 toturn the arm 28 of the injection timing control member 178 little bylittle clockwise in FIG. 43 and FIG. 44, so that the control sleeve 14is moved down with respect to the plunger 8. At the moment when thecontrol sleeve 14 falls and covers the lower edge of the longitudinalgroove 8c of the control groove, the compressed air flow is stopped. Thestoppage of this air flow can be exactly confirmed by the fall of theindicator 184 of the air manometer 170. This position is nothing lessthan an injection starting position. So, at this position, the controlmember 178 is fixed on the control shaft 26 by tightening the bolt orscrew 186.

It can be therefore practiced very simply and quickly to settle theinjection timing of the injection pump for each cylinder with respect toa crank angular position properly set (this is a position in the axialdirection of the cam 12 or the plunger 8 therefore). According to thismethod, a period of time required for settling the injection timing canbe obviously shortened less than one of fractions and the cost can bereduced correspondingly, as compared with a conventional method whichcomprises checking the fuel injection pump by passing fuel therein, andthen taking off the sealing plug 182, carrying out the fine adjustmentof the injection timing control member 178, and passing the fuel throughthe injection pump again, and repeating these works several times.Another method may be utilized in which the control groove is firstblocked up by the control sleeve 14, reversely to the abovementionedmethod, and the control sleeve 14 is caused to rise gradually so thatthe lower end of the control groove is opened by the lower edge of saidsleeve, and the moment when the compressed air begins to flow isconfirmed by the floating-up of the float 184 of the air manometer 170.The aforementioned embodiment has been applied to the injection pump inwhich the control groove is provided on the plunger 8 and the controlports 14a cooperating therewith are provided on the control sleeve 14,and it can be also applied to an injection pump composed so that acontrol groove inclined with respect to the plunger axis is provided onthe side of the control sleeve 14 and control ports communicated withthe oil passage 8a are opened on the outer peripheral surface of theplunger 8. In order to match the fuel injection quantities of theinjection pump for a plurality of cylinders uniformly, furthermore, thelock nut 128 is relaxed and the regulation member 124 is turned by useof a tool such as a screw driver. Then, the plunger guide 114 is causedto turn together with the plunger 8 around its axis by virtue of thecooperation of the eccentric pin 122 and the engagement groove 118 sothat the relative related position of the plunger to the control sleeve14 is varied, and in other words, the relative position of the controlport 14a to the control groove is changed. Thus, the fuel injectionquantities of the injection pump for the respective cylinders are finelyregulated.

After the settling of the injection timings is completed in theabovementioned way, the sealing plug 182 is screw-engaged, the airmanometer 170 is taken off and the delivery valve 7a and spring 7b areset again to fix the delivery valve holder 6 at the given position, andon the other hand, the lock nut 128 is tightened to obstruct the turningof the plunger 8 around its axis. Thus, all the works are completed.

Although the air manometer has been used in the aforementionedembodiment, the same operational effects as the aforementionedembodiment can be obtained by use of an air flow meter or pressure gaugeas a substitute for the air manometer.

We claim:
 1. A fuel injection pump device which comprises: a deliveryvalve communicated with a pressurizing chamber formed in a housing,loaded by a spring and communicated with a fuel injection nozzle; aplunger with its one end facing the pressurizing chamber and the otherend operatively connected with a cam which is driven by an engine; afuel chamber provided so as to surround the plunger in the housing; anoil passage formed in the plunger so that its one end communicates tothe pressurizing chamber and the other end communicates to the fuelchamber; a control sleeve slidably mounted on the outer periphery of theplunger in the fuel chamber; a control groove provided on the outerperipheral surface of the plunger for communicating the pressurizingchamber and fuel chamber to each other by way of the oil passages or forinterrupting the same, said control groove having at leastlongitudinally directed edges and inclined edges provided with relationto the axis of the plunger; control ports provided on the control sleeveand communicating the control groove to the fuel chamber when a fuelinjection is completed; an injection quantity control member supportedon the housing for controlling a fuel injection quantity; an injectiontiming control member for moving the control sleeve in the axialdirection of the plunger; fuel injection control means for controllingthe injection quantity control member and the injection timing controlmember in accordance with signals from operating state informationsources, the fuel injection control means is composed so as to advancethe injection timing control member on the basis of the information ofthe engine in a high speed region from the operating state informationsources; the control groove is provided on the plunger and the controlports on the control sleeve, respectively, and the length between theupper end of the control sleeve and the control ports is set so as to beequal to or shorter than the length between the upper end of thelongitudinally directed edges and the control ports when the plunger isunder the state of the minimum effective stroke by virtue of theoperation of the injection quantity control member and at the positionwhere it has risen to the top, whereby two-stage blasting of fuel isprevented.
 2. A fuel injection pump device, as set forth in claim 1, inwhich when a geometrical average oil feed ratio V_(p) (mm³ /deg) soughtfrom the diameter D (mm) of the plunger and the lift h (mm) of the camis given by the related expression V_(p) =2.47×10⁻² ×D² ×h, thegeometrical average oil feed ratio V_(p) sought from the same relatedexpression V_(p) is made to exist in such a range that the relatedexpression 22.8 V_(s) +12.8≧V_(p) ≧18.8 V_(s) +10.2 is satisfied betweenthe geometrical average oil feed ratio V_(p) and the piston displacementV_(s) (1) per a single cylinder of the engine.
 3. A fuel injection pumpdevice, as set forth in claim 1 or 2, in which the injection quantitycontrol member is composed so as to turn the plunger.
 4. A fuelinjection pump device, as set forth in claim 1 or 2, in which theinjection quantity control member is composed so as to turn the controlsleeve around the plunger.
 5. A fuel injection pump device, as set forthin claim 1 or 2, in which the oil passage is communicated to the fuelchamber by way of at least two oil feed ports, the control groove is cuton the outer periphery of the plunger so as confront each of the oilpassages, and plural control ports are perforated on the control sleeveso as to confront the control grooves.
 6. A fuel injection pump device,as set forth in claim 1 or 2, in which the minimum space between boththe inclined groove and longitudinal groove in the direction in that theinclined groove intersects the longitudinal groove is made shorter thanor equal to the inner diameter of the control ports.
 7. A fuel injectionpump device, as set forth in claim 1 or 2, in which the inclined grooveis formed so as to intersect the portion of the longitudinal grooveother than both its ends, and the length of the longitudinal groove inthe direction of the plunger axis is set to be shorter than the lengthof the control sleeve in its sliding direction to constitute a conditionfor fuel injection and to be larger than the length between the lowerend of the control sleeve and the control ports to constitute acondition for no injection of fuel.
 8. A fuel injection pump device, asset forth in claim 1 or 2, in which the length between the upper end ofthe control sleeve and the control ports is set so as to be equal to orshorter than the length of the longitudinal groove when the plunger isdisplaced with the longitudinal groove and control groove almostaccording with each other by virtue of the operation of the injectionquantity control member, whereby no injection of fuel is obtained.
 9. Afuel injection pump device, as set forth in claim 1 or 2, in which a camprofile is formed whose speed constant is almost constant within a givenrange of the cam angle, in a cam diagram sought by the relation of theangle of the cam and the speed constant of the plunger, and theinjection timing control member is controlled within the given range ofthe cam angle.
 10. A fuel injection pump device, as set forth in claim4, in which the injection quantity control member comprises an operationshaft supported on the housing, an operation lever extended from theoperation shaft, whose end is inserted in the hole on the outerperiphery surface of the control sleeve, and an injection quantityregulation lever in which the operation shaft is retained for rotationaround its axis and which moves the operation shaft in the axialdirection, and the injection timing control member comprises aninjection timing regulation lever in which the operation shaft isretained for movement in its axial direction and which rotates theoperation shaft around its axis.
 11. A fuel injection pump device, asset forth in claim 1, in which the fuel injection control means has ahydraulic piston for driving the injection timing control member, afirst solenoid valve provided between the fuel delivery side of a fuelsystem and the oil chamber of the hydraulic piston, a second solenoidvalve provided between the oil chamber of the hydraulic piston and thefuel recovery side of the fuel system, a position sensor for detectingthe stroke position of the hydraulic piston, and a fuel injection timingcontrol means for controlling the first solenoid valve and the secondsolenoid valve in accordance with the signals from the position sensorand the signals from the operating state information sources.
 12. A fuelinjection pump device, as set forth in claim 1, in which the cam has aninjection part for injecting fuel from the fuel injection nozzle and anauxiliary part for raising the pressure ranging from the pressurizingchamber to the fuel chamber once after completion of the injection ofthe fuel.
 13. A fuel injection pump device, as set forth in claim 4, inwhich the injection quantity control member comprises a rack membermeshing with a gear formed on the outer periphery of the control sleeve,a screw shaft which is screw-engaged with the rack member, and a fixingmeans such as a lock nut for fixing the rack member on the screw shaftadjustably.
 14. A fuel injection pump device, a set forth in claim 4, inwhich the delivery valve is attached in a barrel fixed in the housing byclamping bolts, and the plunger is mounted in the barrel so as to beslidable in the direction of its axis, but not relatively rotated aroundthe axis, wherein the regulation of the fuel injection quantity can becarried out by turning the barrel and the plunger as one body around theplunger axis with respect to the control sleeve.
 15. A fuel injectionpump device, as set forth in claim 4, in which the delivery valve isattached in a barrel fixed in the housing by clamping bolts, the plungeris mounted in the barrel so as to be slidable in the direction of itsaxis, but not relatively rotated around the axis, a plunger guide ismounted near on the lower end of the plunger so that its relativerotation with the plunger is inhibited around the plunger axis, but itsrelative displacement is enabled in the direction of the plunger axis,and a regulation member is rotatably supported in the housing, with itsone end cooperating with the engagement groove of the plunger guide totune the plunger guide around the plunger axis, wherein the regulationof the fuel injection quantity can be carried out by turning theregulation member to turn the plunger around the plunger axis withrespect to the control sleeve by way of the plunger guide, and then theregulation member can be fixed.
 16. A fuel injection pump device, as setforth in claim 1, in which the oil passage has oil feed ports formed atthe other end thereof and communicated to or interrupted from the fuelchamber by means of the control sleeve, and the control groove has afirst side provided slantedly with respect to the plunger axis and asecond side extended in parallel with the plunger axis, in communicationwith the oil passage on the outer peripheral surface of the plunger,wherein the oil feed ports and the control groove are arranged at aninterval around the axis of the plunger.
 17. A fuel injection pumpdevice, as set forth in claim 1 or 2, in which one of the injectiontiming control member and the injection quantity control member isengaged with the control sleeve and the other of the injection timingcontrol member and the injection quantity control member is engaged withsaid one member so that the operation of said one member is nothindered, wherein the injection timing of fuel is controlled by virtueof the operation of the injection timing control member and theinjection quantity of fuel is controlled by virtue of the operation ofthe injection quantity control member.
 18. A fuel injection pump device,as set forth in claim 1, in which the cross-sectional area of theopening of the oil passage to the fuel chamber is made larger than thatof the other portion thereof.